Host-derived pre-existing antibodies generated upon natural encounter of AAV or recombinant AAV vectors prevent first time as well as repeat administration of AAV vectors as vaccines and/or for gene therapy. Serological studies reveal a high prevalence of antibodies in the human population worldwide with about 67% of people having antibodies against AAV1, 72% against AAV2, and about 40% against AAV5 through AAV9.
Furthermore, in gene therapy, certain clinical scenarios involving gene silencing or tissue degeneration may require multiple AAV vector administrations to sustain long term expression of the transgene. To circumvent these issues, recombinant AAV vectors which evade antibody recognition (AAVe) are required. This invention will help a) expand the eligible cohort of patients suitable for AAV-based gene therapy and b) allow multiple, repeat administrations of AAV-based gene therapy vectors.
The present invention overcomes previous shortcomings in the art by providing methods and compositions comprising an adeno-associated virus (AAV) capsid protein, comprising one or more amino acid substitutions, wherein the substitutions introduce into an AAV vector comprising these modified capsid proteins the ability to evade host antibodies.